Polymerizable composition, polymer, and film

ABSTRACT

A polymerizable composition containing a compound represented by the formula (I) or the formula (I′) is useful for formation of films having a high Δn with no coloration. P 1  and P 2  each are a polymerizable group; m1 and m2 each are an integer of from 1 to 10; A 1  to A 4  each are a predetermined cyclic group; R is a hydrogen atom or an alkyl; in the formula (I), Z 1  is —COO—, —COO—, —OCO—CH═CH—, —NHCO— or —NR 1 CO—; L 1  and L 2  each are —O—, —S—, —COO—, —COO—, —OCO—CH═CH—, —OCOO—, —NHCO— or —NR 1 CO; n1 is 1 or 2; in the formula (I′), Z 1  and Z 2  each are —COO—, —OCO—, —NHCO— or NR 1 CO; L 1  and L 2  each are —O—, —S—, —COO—, —OCO—, —OCOO—, —NHCO— or NR 1 CO; n1 and n2 each are 1 or 2.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of International Application No. PCT/JP2011/064256, filed Jun. 22, 2011, which in turn claims the benefit of priority from Japanese Application No. 2010-141467, filed Jun. 22, 2010, and Japanese Application No. 2010-141468, filed Jun. 22, 2010, the disclosures of which applications are incorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a polymerizable composition and a polymer useful in various uses typically for materials for various types of optical members such as optically anisotropic films, heat insulating films, etc., and to a film using any of these.

2. Description of the Related Art

These days downsizing of liquid-crystal display devices is desired, and with that, thinning of optical films is also desired. For example, using a liquid crystal having a high Δn in an optical film such as retardation film or the like makes it possible to reduce the thickness of the film. Δn is one of important basic physical properties of a liquid-crystal compound; and a liquid crystal having a high Δn can be utilized in many industrial fields of retardation plates, polarizing elements, selective reflection films, color filters, antireflection films, viewing angle compensation films, holography, alignment films and others that are constituent elements of optical devices (Non-Patent Document 1).

Heretofore, as a liquid-crystal compound having a large Δn, there are known those having an azomethine structure such as typically MBBA (Non-Patent Document 2). One characteristic feature of a liquid-crystal compound is that the compound has flowability; but in the above-mentioned uses, the flowability of the liquid crystal may be often insufficient and the liquid crystal must be solidified while keeping the desired alignment thereof. As one solution, there is known a polymerizing liquid crystal capable of forming a network structure by introducing a bifunctional or more polyfunctional polymerizable group into a compound having an azomethine structure (Patent Document 1 and Patent Document 2).

CITATION LIST Patent Documents

-   Patent Document 1: JP-A 2007-279363 -   Patent Document 2: JP-A 2007-206461

Non-Patent Documents

-   Non-Patent Document 1: D. J. Broer, G. N. Mol, J. A. M. M. Van     Haaren, and J. LubAdv. Mater., 1999, 11, 573 -   Non-Patent Document 2: Molecular Crystals and Liquid Crystals, 34,     65 (1976)

SUMMARY OF THE INVENTION

However, of the above-mentioned conventional liquid crystals, the compounds having a high Δn are yellowish and therefore have a problem in that they are unsuitable to uses that require colorlessness. Another problem with them is that the temperature range of the liquid-crystal phase thereof is narrow and therefore they may readily crystallize in a polymerization process.

The present invention solves the above-mentioned problems heretofore existing in the art and attains the object mentioned below. Specifically, the object of the invention is to provide a polymerizable composition, a polymer and a film that are useful for production of various types of transparent and colorless optical members by utilizing a polymerizing azomethine compound that has a high Δn and is colorless. In particular, the object of the invention is to provide a polymerizable composition, a polymer and a film that are useful for production of retardation films and selective reflection films required to be thin and have highly-functional characteristics.

The means for solving the above-mentioned problems are as follows:

[1] A polymerizable composition containing at least one compound represented by the following formula (I):

wherein P¹ and P² each represent a polymerizable group; m1 and m2 each indicate an integer of from 1 to 10, and of m1 or m2 CH₂'s, one CH₂ or two or more CH₂'s not adjacent to each other may be replaced by an oxygen atom or a sulfur atom; A¹, A² and A³ each represent a substituted or unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue; R represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; Z¹ represents —COO—, —COO—, —OCO—CH═CH—, —NHCO— or —NR¹CO—, and R¹ represents an alkyl group having from 1 to 10 carbon atoms; L¹ and L² each represent —O—, —S—, —COO—, —COO—, —OCO—CH═CH—, —OCOO—, —NHCO— or —NR¹CO, and R¹ represents an alkyl group having from 1 to 10 carbon atoms; n1 is 1 or 2. [2] The polymerizable composition of [1], wherein A¹, A² and A³ each are an unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue, or at least one of A¹, A² and A³ is a 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue substituted with an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, an amide group having from 2 to 5 carbon atoms, an alkoxycarbonyl group having from 2 to 5 carbon atoms, an acyloxy group having from 2 to 5 carbon atoms, an acyl group having from 2 to 5 carbon atoms, a cyano group or a halogen atom. [3] The polymerizable composition of [1] or [2], wherein, in the formula (I), n1 is 1, and A¹, A² and A³ each are a substituted or unsubstituted 1,4-phenylene group. [4] The polymerizable composition of any of [1] to [3], wherein, in the formula (I), L¹ and L² each are —O—, and Z¹ is —OCO— or —OCO—CH═CH—. [5] A polymerizable composition containing at least one compound represented by the following formula (I′):

wherein P¹ and P² each represent a polymerizable group; m1 and m2 each indicate an integer of from 1 to 10, and of m1 or m2 CH₂'s, one CH₂ or two or more CH₂'s not adjacent to each other may be replaced by an oxygen atom or a sulfur atom; A¹, A², A³ and A⁴ each represent a substituted or unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5 to 18-membered aromatic hetero ring residue; R represents a hydrogen atom or an alkyl group having from 1 to 8 carbon atoms; Z² and Z² each represent —COO—, —OCO—, —NHCO— or —NR²CO—, and R² represents an alkyl group having from 1 to 10 carbon atoms; L¹ and L² each represent —O—, —S—, —COO—, —OCO—, —OCOO—, —NHCO— or —NR²CO, and R² represents an alkyl group having from 1 to 10 carbon atoms; n1 and n2 each are 1 or 2. [6] The polymerizable composition of [5], wherein, in the formula (I′), A² and A³ each are 1,4-phenylene optionally having a substituent, and n1=n2=1. [7] The polymerizable composition of [6], wherein, in the formula (I′), A¹ and A⁴ each are 1,4-phenylene. [8] The polymerizable composition of any of [5] to [7], wherein A¹, A², A³ and A⁴ each represent an unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue, or at least one of A¹, A², A³ and A⁴ is a 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue substituted with an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, an amide group having from 2 to 5 carbon atoms, an alkoxycarbonyl group having from 2 to 5 carbon atoms, an acyloxy group having from 2 to 5 carbon atoms, an acyl group having from 2 to 5 carbon atoms, a cyano group or a halogen atom. [9] The polymerizable composition of any of [1] to [8], wherein, in the formulae (I) and (I′), P² and P² each are a polymerizable group selected from the groups represented by the following formulae (P-1) to (P-5):

wherein R¹¹ to R¹³ each represent a hydrogen atom or a methyl group. [10] The polymerizable composition of any of [1] to [9], wherein, in the formulae (I) and (I′), P¹ and P² each are a methacrylate group or an acrylate group. [11] The polymerizable composition of any of [1] to [10], wherein, in the formulae (I) and (I′), m1 and m2 each are an integer of from 2 to 8. [12] The polymerizable composition of [11], containing at least one chiral compound. [13] A polymer produced by polymerizing the polymerizable composition of any of [1] to [12]. [14] A film containing at least one polymer of [13]. [15] A film produced by fixing the cholesteric liquid-crystal phase of the polymerizable composition of any of [1] to [12]. [16] The film of [14] or [15], which shows optical anisotropy. [17] The film of any of [14] to [16], which shows selective reflection characteristics. [18] The film of [17], which shows selective reflection characteristics in the IR wavelength range.

According to the invention, there are provided a polymerizable composition, a polymer and a film that are useful for production of various types of transparent and colorless optical members by utilizing a polymerizing azomethine compound that has a high Δn and is colorless. In particular, the invention can provide a polymerizable composition, a polymer and a film that are useful for production of optical films such as retardation films, selective reflection films and others required to be thin and have desired optical characteristics.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 This shows absorption spectrum curves of compounds of the formula (I) and a comparative compound, as measured in Examples.

FIG. 2 This shows enlarged graphs of the absorption spectrum curves in FIG. 1.

FIG. 3 This shows absorption spectrum curves of compounds of the formula (I′) and a comparative compound, as measured in Examples.

FIG. 4 This shows enlarged graphs of the absorption spectrum curves in FIG. 3.

MODE FOR CARRYING OUT THE INVENTION

The invention is described in detail hereinunder. In this description, the numerical range expressed by the wording “a number to another number” means the range that falls between the former number indicating the lower limit of the range and the latter number indicating the upper limit thereof.

1. Polymerizable Composition

The invention relates to a polymerizable composition containing at least one compound represented by the formulae (I) and (I′) mentioned below. The compounds represented by the following formulae (I) and (I′) are characterized by having one azomethine group in the molecule along with a mesogen therein. A liquid-crystal compound having an azomethine group in the molecule shows a high Δn, but on the other hand, a conventional bisazomethine liquid-crystal compound having two azomethine groups in the molecule is yellowish and therefore its use is limited. The compounds of the following formulae (I) and (I′) show a sufficiently high Δn and are white, and therefore these are free from a problem of coloration. Further, in the compounds of the following formulae (I) and (I′), the side chain that links the terminal polymerizable group to the mesogen therein is long, and therefore the temperature range in which the compounds are in a liquid phase could be broad. Consequently, the compounds solve the problem that they may crystallize in a polymerization process to be cloudy. Further, the solubility of the compounds insolvent and the miscibility thereof with any other liquid crystal material are both good, and they can cure through polymerization. Consequently, the compounds are useful in various applications for optical members, etc. In particular, since their Δn is high, the compounds are useful in production of optical films such as retardation films, selective reflection films and others that are required to show desired optical characteristics in the form of thin films.

In the formula (I), P¹ and P² each represent a polymerizable group;

m1 and m2 each indicate an integer of from 1 to 10; and of m1 or m2 CH₂'s, one CH₂ or two or more CH₂'s not adjacent to each other may be replaced by an oxygen atom or a sulfur atom;

A¹, A² and A³ each represent a substituted or unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue;

R represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms;

Z¹ represents —COO—, —COO—, —OCO—CH═CH—, —NHCO— or —NR¹CO—, and R¹ represents an alkyl group having from 1 to 10 carbon atoms;

L¹ and L² each represent —O—, —S—, —COO—, —OCO—, —OCO—CH═CH—, —OCOO—, —NHCO— or —NR¹CO, and R¹ represents an alkyl group having from 1 to 10 carbon atoms;

n1 is 1 or 2.

In the formula (I′), P¹ and P² each represent a polymerizable group;

m1 and m2 each indicate an integer of from 1 to 10, and of m1 or m2 CH₂'s, one CH₂ or two or more CH₂'s not adjacent to each other may be replaced by an oxygen atom or a sulfur atom; A¹, A², A³ and A⁴ each represent a substituted or unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue; R represents a hydrogen atom or an alkyl group having from 1 to 8 carbon atoms; Z¹ and Z² each represent —COO—, —OCO—, —NHCO— or —NR¹CO, and R¹ represents an alkyl group having from 1 to 10 carbon atoms; L¹ and L² each represent —O—, —S—, —COO—, —OCO—, —OCOO—, —NHCO— or —NR¹CO, and R¹ represents an alkyl group having from 1 to 10 carbon atoms; n1 and n2 each are 1 or 2.

In the above-mentioned formulae (I) and (I′), P¹ and P² each represent a polymerizable group. The polymerizable group is preferably a radical-polymerizable or cationic-polymerizable polymerizable group. As the radical-polymerizable group, any radical-polymerizable group generally known in the art is usable here, and one preferred example thereof is a (meth)acrylate group (this is used as a term including both an acrylate group and a methacrylate group). In this case, it is known that the polymerization rate is generally high with an acrylate group, and therefore an acrylate group is preferable from the viewpoint of productivity improvement; however, a methacrylate group is also usable similarly as the polymerizable group in high-Δn liquid crystals. As the cationic-polymerizable group, any cationic-polymerizable group generally known in the art is usable here; and concretely, there are mentioned an alicyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro-orthoester group, a vinyloxy group, etc. Of those, preferred are an alicyclic ether group and a vinyloxy group, and more preferred are an epoxy group, an oxetanyl group, and a vinyloxy group. In the above-mentioned formulae, P¹ and P² may be the same or different; or that is, the compound of the above-mentioned formulae (I) and (I′) may contain two or more different types of polymerizable groups. In that case, the compound may have polymerizable groups that differ in point of the polymerization reaction mechanism thereof, such as a radical-polymerizable group and a cationic-polymerizable group, etc., or may have polymerizable groups having the same reaction mechanism.

Preferably, P¹ and P² each are a polymerizable group represented by any of the following formulae (P-1) to (P-5):

In the formulae, R¹¹ to R¹³ each represent a hydrogen atom or a methyl group. * indicates the position at which the group bonds to the alkylene chain in the formulae.

Preferably, P¹ and P² each are a (meth)acrylate group, or that is, any of the following groups:

In the above-mentioned formulae (I) and (I′), m1 and m2 each indicate an integer of from 1 to 10. When the side chain is short (for example, when m1 and m2 each are from 1 to 3), then the uppermost temperature at which the compound can exhibit a liquid-crystal phase is high, but the compound may readily crystallize and its solubility lowers. Consequently, from the viewpoint of the solubility or the miscibility of the compound in or with any other ingredient (e.g., solvent or other liquid-crystal material) to be contained in the composition, the proportion of the compound of the type must be small. On the other hand, when the side chain is long (for example, when m1 and m2 each are from 4 to 6), then the solubility of the compound may increase but the uppermost temperature at which the compound can exhibit a liquid-crystal phase may lower or the compound may readily exhibit a smectic phase and the nematic liquid range of the compound may be narrow so that the alignment uniformity of the compound may lower. In addition, when the side chain is long, then the degree of freedom of the molecule movement may increase. Therefore, in the field of use where a highly rigid film quality is desired, it is desirable to use a compound having a short side chain. However, in the field of use where a non-brittle film is desired, it is desirable to use a compound having a long side chain. Of m1 or m2 CH₂'s in the above-mentioned formulae (I) and (I′), one CH₂ or two or more CH₂'s not adjacent to each other may be replaced by an oxygen atom or a sulfur atom. In the compound where —CH₂— is replaced by S or O, the rotation capacity around the linking group increases, or that is, the degree of freedom therearound increases, and therefore the compound of the type is effective for reducing film brittleness. Preferably, the nematic phase range of the compound of the above-mentioned formulae (I) and (I′) is enlarged as compared with that of other conventional azomethine compounds; and from this viewpoint, m1 and m2 each are preferably from 2 to 8, more preferably from 3 to 6.

Type and Number of Rings:

For attaining high Δn, the alignment regularity must be high, and for this, it is effective to raise the uppermost temperature for the liquid-crystal phase. The compound of the above-mentioned formula (I) for use in the composition of the invention is so designed that at least three cyclic aromatic groups (A¹ to A³ in the formula (I)) are linked to each other, and from the characteristic of the molecular structure thereof, the NI point (transition temperature from nematic liquid-crystal phase to isotropic phase) is high, and concretely, the compound shows an extremely high NI point of 160° C. or higher, therefore greatly contributing toward increasing Δn of the composition. When the number of the rings that link to each other via a suitable linking group is 4, then the NI point of the compound can be further raised with no coloration trouble, and Δn thereof may be therefore increased. The compound of the formula (I′) is so designed that at least four cyclic aromatic groups (A¹ to A⁴ in the formula (I′)) are linked to each other, and from the characteristic of the molecular structure thereof, the NI point (transition temperature from nematic liquid-crystal phase to isotropic phase) is high, and concretely, the compound shows an extremely high NI point of 180° C. or higher, therefore greatly contributing toward increasing Δn of the composition. When the number of the rings that link to each other via a suitable linking group is 5 or 6, then the NI point of the compound can be further raised with no coloration trouble, and Δn thereof may be therefore increased. In addition, the aromatic ring increases the polarization degree in the long axis direction of the molecule, as compared with an unsaturated ring or a nonaromatic ring, therefore contributing toward increasing Δn of the compound. However, increasing the number of the rings may elevate or increase the melting point or the viscosity of the compound, and is therefore defective in the region where the compound is used for optical films in that the compound would readily crystallize in a coating process to worsen film uniformity.

In the formula (I), A¹, A² and A³ each represent a substituted or unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue. A¹ to A³ each may be a single ring residue or a condensed ring residue including two or more rings. However, from the viewpoint of more reducing coloration, preferred is a single ring residue. Two or more rings may form a condensed ring structure where two or more rings are condensed; or the same or different, two or more single rings or condensed rings may be bonded via a saturated bond or an unsaturated bond (preferably an unsaturated bond, more preferably a triple bond (—C≡C—) to form a bonded structure. The single ring structure is preferably a 5- to 7-membered ring structure, more preferably a 5- or 6-membered ring structure. The ring-constitutive atoms of the hetero ring are preferably one or more selected from a nitrogen atom, a sulfur atom and an oxygen atom.

In the formula (I′), A¹, A², A³ and A⁴ each represent a substituted or unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue. A¹ to A⁴ each may be a single ring residue or a condensed ring residue including two or more rings. However, from the viewpoint of more reducing coloration, preferred is a single ring residue. The single ring structure is preferably a 5- to 7-membered ring structure, more preferably a 5- or 6-membered ring structure. The ring-constitutive atoms of the hetero ring are preferably one or more selected from a nitrogen atom, a sulfur atom and an oxygen atom.

Examples of A¹ to A³ in the formula (I) and those of A¹ to A⁴ in the formula (I′) are shown below, to which, however, the invention is not limited.

In the formula (I), A¹ to A³ each are preferably a divalent group having a 6-membered aromatic hydrocarbon ring and optionally having a substituent, more preferably a 6-membered aromatic hydrocarbon ring residue optionally having a substituent, or that is, a phenylene group optionally having a substituent, and even more preferably a 1,4-phenylene group optionally having a substituent. In case where A¹ to A³ each are a condensed ring residue optionally having a substituent, they each are preferably a naphthalene ring residue optionally having a substituent.

In the formula (I′), A¹ to A⁴ each are preferably a single ring residue (for example, the above-exemplified single ring residue) optionally having a substituent, or preferably a divalent group having a 6-membered aromatic hydrocarbon ring, more preferably a 6-membered aromatic hydrocarbon ring residue optionally having a substituent, or that is, a phenylene group optionally having a substituent, and even more preferably a 1,4-phenylene group optionally having a substituent. In case where A¹ to A⁴ each are a condensed ring residue optionally having a substituent, they each are preferably a naphthalene ring residue optionally having a substituent.

Type and Number of Substituents:

For high Δn, long wave absorption is effective, which, however, is a cause of coloration by conventional bisazomethine-type liquid-crystal compounds. In the compound of the formula (I) in the invention, the type of the substituent on the two aromatic rings that are linked to each other via the azomethine bond therein has little influence on color development of the compound, and consequently, compounds having any arbitrary substituent are usable here. From the viewpoint of the solubility of the compound, the substituents having atoms larger in size could more contribute toward the solubility, but those having atoms smaller in size lower the solubility and the alignability of the compound may also lower. From these, the compound preferably has substituents. Regarding the number of the substituents, when the number is larger, the solubility of the compound may be expected to increase more; but if too large, the liquid crystallinity of the compound may worsen.

In the formula (I), examples of the substituents which A¹ to A³ may have include an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, an amide group having from 2 to 5 carbon atoms, an alkoxycarbonyl group having from 2 to 5 carbon atoms, an acyloxy group having from 2 to 5 carbon atoms, an acyl group having from 2 to 5 carbon atoms, a cyano group, and a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom and iodine atom). More preferred are an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, an amide group having from 2 to 5 carbon atoms, an alkoxycarbonyl group having from 2 to 5 carbon atoms, and a halogen atom; and even more preferred are an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, an alkoxycarbonyl group having from 1 to 4 carbon atoms, and a halogen atom.

In the formula (I′), examples of the substituents which A¹ to A⁴ may have include an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, an amide group having from 2 to 5 carbon atoms, an alkoxycarbonyl group having from 2 to 5 carbon atoms, an acyloxy group having from 2 to 5 carbon atoms, an acyl group having from 2 to 5 carbon atoms, a cyano group, and a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom and iodine atom). More preferred are an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, an amide group having from 2 to 4 carbon atoms, an alkoxycarbonyl group having from 2 to 5 carbon atoms, and a halogen atom; and even more preferred are an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, an alkoxycarbonyl group having from 2 to 5 carbon atoms, and a halogen atom.

In view of these, the number of the rings in the compound of the formulae (I) and (I′) is preferably smaller. n1 is 1 or 2 but is preferably 1.

In the formulae (I) and (I′), R represents a hydrogen atom or an alkyl group having from 1 to 8 carbon atoms. Even when R is a hydrogen atom, the compound has sufficient hydrolysis resistance; however, for uses that require extremely high hydrolysis resistance, the compound where R is an alkyl group is preferably used. Regarding the length of the alkyl group, when the group is too long, it may make the liquid phase of the compound unstable; and consequently, R is preferably shorter. Concretely, R is preferably an alkyl group having from 1 to 8 carbon atoms, more preferably an alkyl group having from 1 to 5 carbon atoms, even more preferably an alkyl group having from 1 to 3 carbon atoms.

In the formula (I), Z² represents —COO—, —OCO—, —OCO—CH═CH—, —NHCO— or —NR¹CO—, and R² represents an alkyl group having from 1 to 10 carbon atoms; more preferably, Z² is —COO—, —OCO— or —OCO—CH═CH—, even more preferably —OCO— or —OCO—CH═CH—.

In the formula (I), L² and L² each represent —O—, —S—, —COO—, —OCO—, —OCO—CH═CH—, —OCOO—, —NHCO— or —NR¹CO, and R¹ represents an alkyl group having from 1 to 10 carbon atoms; more preferably L² and L² each are —O—, —S—, —COO—, —OCO— or —OCOO—, even more preferably —O—, —OCO— or —OCOO—.

Type of Linking Group:

As the linking groups that link the ring structures (Z² and Z² in the formula (I′)), preferred are those having a rigid structure for stabilizing the liquid phase (that is, for raising the NI point). On the other hand, when too many rigid groups exist in the compound, then the solubility of the compound may lower owing to the increase in the crystallinity thereof, and the nematic liquid-crystal phase temperature range may narrow owing to stabilization of the smectic phase of the compound. From these viewpoints, the linking groups are preferably so selected that the nematic liquid-phase of the compound could be stabilized. Concretely, in the above-mentioned formula, Z¹ and Z² each represent —COO—, —OCO—, —NH— or NR¹, and R¹ represents an alkyl group having from 1 to 10 carbon atoms; and more preferably, Z¹ and Z² each are —COO—, —OCO— or —NH—, even more preferably —COO— or —OCO—.

In the formula (I′), L¹ and L² each represent —O—, —S—, —COO—, —OCO—, —OCOO—, —NH— or NR¹, and R¹ represents an alkyl group having from 1 to 10 carbon atoms; and more preferably, L¹ and L² each are —O—, —S—, —COO—, —OCO— or —OCOO—, even more preferably —O— or —OCOO—. The type of the linking groups mentioned above has little influence on the absorbability of the entire compound (or that is, on the color development of the compound).

Specific examples of the compound represented by the above-mentioned formula (I) are given below; however, the invention is not limited at all to these specific examples.

Specific examples of the compound represented by the above-mentioned formula (I′) are given below; however, the invention is not limited at all to these specific examples.

The compound represented by the general formula (I) in the invention may be produced, for example, according to the reaction formula (1) mentioned below.

In the above-mentioned reaction formula (1), L³ represents O, S, NH or NR¹; A¹ to A³, Z¹, L¹, L², R, R¹, P¹ and P² have the same meanings as those in the general formula (I), and their preferred ranges are also the same as therein.

The compound represented by the general formula (I′) in the invention may be produced, for example, according to the reaction formula (2) mentioned below.

In the above-mentioned reaction formula (2), L³ and L⁴ each represent O, S, NH or NR¹; A¹ to A⁴, Z¹, Z², L¹, L², R, R¹, P¹ and P² have the same meanings as those in the general formula (I′), and their preferred ranges are also the same as therein.

In the reaction formulae (1) and (2), the compound (A) is an aromatic aldehyde, and may be one produced with reference to [0067] to [0074] on pages 14 and 15 in JP-A 2002-97170. In the reaction formula (1), the compound (B) is an aminophenol, aminothiophenol or diaminobenzene derivative, and may be a commercial product or may be one produced according to a known method. The compound (D) and the compound (E) may be produced according to the method described in paragraphs [0085] to [0087] on page 10 in JP-A 2002-97170, or according to the method described in paragraphs [0109] to [0110] on page 23 in Japanese Patent 4355406, etc.

Specifically, the compound represented by the general formula (I) can be produced by preparing the compound (C) through dehydrating condensation of the compound (A) and the compound (B) followed by reaction of the compound (C) and the compound (D) according to the reaction formula (1); and the compound represented by the general formula (I′) can be produced by preparing the compound (C) through dehydrating condensation of the compound (A) and the compound (B) followed by reaction of the compound (C), the compound (D) and the compound (E) according to the reaction formula (2).

For preventing thermal polymerization during the reaction, a polymerization inhibitor such as a hydroquinone derivative or the like may be added to the system.

The compound represented by the formulae (I) and (I′) to be contained in the polymerizable composition of the invention exhibits liquid crystallinity. Further, the compound has a high Δn, and therefore the film in which the orientation of the compound has been fixed is expected to attain the desired optical characteristics even though it is thinner, as compared with the film that uses a liquid-crystal compound having a lower Δn.

In addition, the compound has an extremely small absorption in the visible light region, irrespective of the type of the substituents on the aromatic rings therein and of the linking groups therein, and is therefore colorless and transparent; and further, the compound satisfies other various characteristics in that it readily dissolves in solvent as the liquid-phase range thereof is broad, and that it readily polymerizes. The cured film to be produced by the use of the polymerizable composition of the invention that contains the compound of the general formula (I) or (I′) could satisfy various characteristics in that it shows a sufficient hardness and is colorless and transparent and that its weather resistance and heat resistance are good. Accordingly, the cured film formed by the use of the polymerizable composition of the invention can be utilized in various uses, for example, for retardation plates, polarizing elements, selective reflection films, color filters, antireflection films, viewing angle compensation films, holography, alignment films and others that are constituent elements of optical devices.

One embodiment of the composition of the invention is a polymerizable composition containing at least one compound of the above-mentioned general formulae (I) and (I′) and at least one chiral compound. The film produced by converting the composition of this embodiment into a cholesteric liquid-crystal phase followed by fixing it exhibits selective reflection characteristics against a light falling within a predetermined wavelength range in accordance with the helical pitch of the phase, and is useful as a reflection film (for example, IR-reflection film). One advantage of using the polymerizing compound that has a high Δn in the invention is that the reflection wavelength range for the film formed of the compound can be broadened as compared with the film having the same thickness but produced by the use of a liquid-crystal compound having a lower Δn.

In the composition of the invention, the compound of the formula (I) or (I′) may be the main ingredient or may be an additive thereto. So far as the composition contains the compound of the general formula (I) or (I′) in an amount of at least 5% by mass relative to the entire mass of the composition, the composition can enjoy the effect of the compound of the formula (I) or (I′), but preferably, the content of the compound is from 10 to 85% by mass, more preferably from 10 to 75% by mass, even more preferably from 15 to 70% by mass. However, the content is not limited to the range.

(1) Chiral Compound

For preparing the composition of the invention as a composition that shows a cholesteric liquid-crystal phase, preferably, a chiral compound is added thereto. The chiral compound may be a liquid-crystalline or non-liquid-crystalline one. The chiral compound may be selected from various known chiral agents (for example, described in Liquid-Crystal Device Handbook, Chap. 3, Item 4-3, “Chiral Agents for TN, STN”, p. 199, edited by Japan Society for the Promotion of Science, 142nd Committee, 1989). Chiral compounds generally contain an asymmetric carbon atom; however, axial asymmetric compounds or planar asymmetric compounds not containing an asymmetric carbon atom are also usable here. Examples of axial asymmetric compounds or planar asymmetric compounds include binaphthyl, helicene, paracyclophane and their derivatives. The chiral compound (chiral agent) for use herein may have a polymerizable group. In case where the chiral compound has a polymerizable group and the rod-shaped liquid-crystal compound to be used here along with the former also has a polymerizable group, a polymer may be formed which has a recurring unit derived from the rod-shaped liquid-crystal compound and a recurring unit derived from the chiral compound, through polymerization of the polymerizing chiral compound and the polymerizing rod-shaped liquid-crystal compound. In this embodiment, preferably, the polymerizable group that the polymerizing chiral compound has is the same type as that of the polymerizable group that the polymerizing rod-shaped liquid-crystal compound has. Accordingly, it is desirable that the polymerizable group of the chiral compound is also an unsaturated polymerizable group, an epoxy group or an aziridinyl group, more preferably an unsaturated polymerizable group, even more preferably an ethylenic unsaturated polymerizable group.

Preferably, the amount of the chiral compound to be in the composition of the invention is from 1 to 30 mol % relative to the compound of the general formula (I) or (I′) in the composition. Preferably, the amount of the chiral compound to be used is smaller for favorably reducing the influence of the compound on the liquid crystallinity of the composition. Accordingly, the chiral compound is preferably a high-torsion compound in order that the compound can attain the desired helical pitch torsion orientation even though its amount is small. As the chiral agent of the type that exhibits such a strong torsion force, for example, there are mentioned the chiral agents described in JP-A 2003-287623, and these are favorably used in the invention.

(2) Other Liquid-Crystal Compound

The composition of the invention may contain one or more other liquid-crystal compounds along with the compound of the above-mentioned formula (I) or (I′). The compound of the formula (I) or (I′) is highly miscible with any other liquid-crystal compound, and therefore, even when any other liquid-crystal compound is mixed in the composition, it does not cause opacification and the composition still may form a film having high transparency. As capable of being mixed with any other liquid-crystal compound in the invention, there can be provided various types of compositions applicable to various uses. Examples of the other liquid-crystal compounds usable here include rod-shaped nematic liquid-crystal compounds. Examples of rod-shaped nematic liquid-crystal compounds include azomethines, azoxy compounds, cyanobiphenyls, cyanophenyl esters, benzoates, phenyl cyclohexanecarboxylates, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolans and alkenylcyclohexylbenzonitriles, Not only low-molecular liquid-crystal compounds but also high-molecular liquid-crystal compounds can be used here.

The other liquid-crystal compounds usable in the invention may be polymerizing ones or non-polymerizing ones. Rod-shaped liquid-crystal compounds not having a polymerizing compound are described in many publications (for example, Y. Goto et. al., Mol. Cryst. Liq. Cryst. 1995, Vol. 260, pp. 23-28).

Polymerizing rod-shaped liquid-crystal compounds may be obtained by introducing a polymerizable group into rod-shaped liquid-crystal compounds. Examples of the polymerizable group include an unsaturated polymerizable group, an epoxy group and an aziridinyl group. Preferred is an unsaturated polymerizable group, and more preferred is an ethylenic unsaturated polymerizable group. The polymerizable group may be introduced into the molecule of a rod-shaped liquid-crystal compound according to various methods. The number of the polymerizable groups which the polymerizing rod-shaped liquid-crystal compound has is preferably from 1 to 6, more preferably from 1 to 3. Examples of the polymerizing rod-shaped liquid-crystal compound include the compounds described in Makromol. Chem., Vol. 190, p. 2255 (1989); Advanced Materials, Vol. 5, p. 107 (1993); U.S. Pat. Nos. 4,683,327, 5,622,648, 5,770,107; WO95/22586, WO95/24455, WO97/00600, WO98/23580, WO98/52905; JP-A 1-272551, 6-16616, 7-110469, 11-80081, 2001-328973, etc. Two or more different types of polymerizing rod-shaped liquid-crystal compounds may be used here as combined. Using two or more different types of polymerizing rod-shaped liquid-crystal compounds as combined lowers the orientation temperature thereof.

The amount of the other liquid-crystal compound to be added is not specifically defined. The content of the compound of the above-mentioned formula (I) or (I′) in the composition may be high, or the content of the other liquid-crystal compound therein may be high, or the two may be the same. Anyhow, the content of the compound may be controlled to fall within a preferred range depending on the use of the composition.

(3) Polymerization Initiator

Preferably, the composition of the invention contains a polymerization initiator. For example, in an embodiment where curing reaction is attained through UV irradiation to form a cured film, the polymerization initiator to be used is preferably a photopolymerization initiator having the ability to initiate polymerization through UV irradiation. Examples of the photopolymerization initiator include α-carbonyl compounds (described in U.S. Pat. Nos. 2,367,661, 2,367,670), acyloin ethers (described in U.S. Pat. No. 2,448,828), α-hydrocarbon-substituted aromatic acyloin compounds (described in U.S. Pat. No. 2,722,512), polynuclear quinone compounds (described in U.S. Pat. Nos. 3,046,127, 2,951,758), combination of triarylimidazole dimer and p-aminophenyl ketone (described in U.S. Pat. No. 3,549,367), acridine compounds and phenazine compounds (described in JP-A 60-105667 and U.S. Pat. No. 4,239,850), and oxadiazole compounds (described in U.S. Pat. No. 4,212,970), etc.

The amount of the photopolymerization initiator to be used is preferably from 0.1 to 20% by mass of the composition (or the solid content thereof when the composition is a coating liquid), more preferably from 1 to 8% by mass.

(4) Alignment Controlling Agent

An alignment controlling agent capable of contributing toward stable or rapid conversion into liquid-crystal phase (for example, cholesteric liquid-crystal phase) may be added to the composition of the invention. Examples of the alignment controlling agent include fluorine-containing (meth)acrylate polymers, and compounds represented by the following general formulae (X1) to (X3). Two or more selected from these may be added to the composition. The compounds reduce the tilt angle of the molecules of a liquid-crystal compound in the layer-to-air interface, or enable substantial horizontal alignment of the molecules therein. In this description, “horizontal alignment” means that the long axis of the liquid-crystal molecule is parallel to the film plane, but this does not require a severe parallel state; and in this description, this means an alignment state of such that the tile angle to the horizontal plane is less than 20 degrees. In case where a liquid-crystal compound is horizontally aligned in the vicinity of the air interface, alignment defects hardly occur, and therefore the transparency of the formed film in the visible light region could be high. On the other hand, when the molecules of a liquid-crystal compound are aligned at a large tilt angle, and for example, when the compound is converted to show a cholesteric liquid-crystal phase, then the helical axis thereof may be shifted from the normal line relative to the film plane, therefore causing some disadvantages in that the reflectivity of the film may lower and the finger print pattern may occur thereby bringing about haze increase and diffractivity expression.

Examples of the fluorine-containing (meth)acrylate polymer usable as the alignment controlling agent are described in JP-A 2007-272185, [0018] to [0043].

The following general formulae (X1) to (X3) usable as the alignment controlling agent here are described in order.

In the formula, R¹, R² and R³ each independently represent a hydrogen atom or a substituent; X¹, X² and X³ each represent a single bond or a divalent linking group. Preferred examples of the substituent represented by R¹ to R³ include a substituted or unsubstituted, alkyl group (above all, more preferred is an unsubstituted alkyl group or a fluorine-substituted alkyl group) or aryl group (above all, more preferred is an aryl group having a fluorine-substituted alkyl group), a substituted or unsubstituted amino group, an alkoxy group, an alkylthio group, and a halogen atom. The divalent linking group represented by X¹, X² and X³ is preferably a divalent linking group selected from an alkylene group, an alkenylene group, a divalent aromatic group, a divalent heterocyclic residue, —CO—, —NRa- (Ra represents an alkyl group having from 1 to 5 carbon atoms, or a hydrogen atom), —O—, —S—, —SO—, —SO₂— or their combinations. The divalent linking group is more preferably a divalent linking group selected from groups of an alkylene group, a phenylene group, —CO—, —NRa-, —O—, —S— and —SO₂—, or a divalent group comprising a combination of at least two groups selected from those groups. The number of the carbon atoms constituting the alkylene group is preferably from 1 to 12. The number of the carbon atoms constituting the alkenylene group is preferably from 2 to 12. The number of the carbon atoms constituting the divalent aromatic group is preferably from 6 to 10.

In the formula, R represents a substituent; and m indicates an integer of from 0 to 5. When m is an integer of 2 or more, plural R's may be the same or different. Preferred examples of the substituent of R are the same as those mentioned hereinabove as preferred examples of the substituent of R¹, R² and R³. m is preferably an integer of from 1 to 3, more preferably 2 or 3.

In the formula, R⁴, R⁵, R⁶, R⁷, R⁸ and R⁹ each independently represent a hydrogen atom or a substituent. Preferred examples of the substituent represented by R⁴, R⁵, R⁶, R⁷, R⁸ and R⁹ are the same as those mentioned hereinabove as the substituent represented by R¹, R² and R³ in the general formula (XI).

Examples of the compounds represented by the above-mentioned formulae (X1) to (X3), which are usable as the alignment controlling agent in the invention, include the compounds described in JP-A 2005-99248.

In the invention, one alone or two or more of the compounds represented by the general formulae (X1) to (X3) may be used as the alignment controlling agent, either singly or as combined.

The amount of the compound represented by any of the general formulae (X1) to (X3) in the composition is preferably from 0.01 to 10% by mass of the mass of the compound of the above-mentioned formula (I), more preferably from 0.01 to 5% by mass, even more preferably from 0.02 to 1% by mass.

(5) Other Additive

The composition of the invention may contain one or more other additives of, for example, antioxidant, UV absorbent, sensitizer, stabilizer, plasticizer, chain transfer agent, polymerization inhibitor, defoaming agent, leveling agent, thickener, flame retardant, surfactant, dispersing agent, colorant such as dye, pigment, etc.

2. Film

The composition of the invention is useful as a material for various optical films such as retardation films, reflection films, etc.

The invention also relates to a film formed of the polymerizable composition of the invention that contains at least one compound of the above-mentioned formula (I) or (I′). The polymerizable composition of the invention is useful as a material for various optical films such as retardation films, reflection films, etc.

(1) Production Method for Film of the Invention

One example of the production method for the film of the invention is a production method that includes at least:

(i) applying the composition of the invention onto the surface of a substrate or the like to make the composition in a state of a liquid-crystal phase (cholesteric liquid-crystal phase, etc.), and

(ii) curing the composition to thereby fix the liquid-crystal phase to form a cured film.

The steps (i) and (ii) may be repeated multiple times to produce a film in which a plurality of the above-mentioned cured films are laminated.

In the step (i), first, the composition of the invention is applied onto a substrate or onto the surface of an alignment film formed on a substrate. Preferably, the composition is prepared as a coating liquid in which the material is dissolved and/or dispersed in a solvent. The solvent to be used in preparing the coating liquid is preferably an organic solvent. The organic solvent includes amides (e.g., N,N-dimethylformamide); sulfoxides (e.g., dimethyl sulfoxide); heterocyclic compounds (e.g., pyridine); hydrocarbons (e.g., benzene, hexane); alkyl halides (e.g., chloroform, dichloromethane); esters (e.g., methyl acetate, butyl acetate); ketones (e.g., acetone, methyl ethyl ketone); ethers (e.g., tetrahydrofuran, 1,2-dimethoxyethane); 1,4-butanediol diacetate, etc. Of those, especially preferred are alkyl halides and ketones. Two or more different types of organic solvents may be used here as combined.

Coating with the coating liquid may be attained according to various methods such as a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die coating method, etc. Using an inkjet apparatus, the composition may be jetted out through the nozzle thereof to form a coating film.

Next, the composition applied onto the surface to form a coating film thereon is converted into a liquid-crystal phase such as a cholesteric liquid-crystal phase, etc. In an embodiment where the composition is prepared as a coating liquid that contains a solvent, the coating film may be dried to remove the solvent, whereby the film may be in a state of liquid-crystal phase. For making the coating film kept at a transition temperature to be a liquid-crystal phase, if desired, the coating film may be heated. For example, the coating film may be once heated up to a temperature of the anisotropic phase thereof, and then it may be cooled to the liquid-crystal phase transition temperature thereof, whereby the coating film can be stably in a state of liquid-crystal phase. The liquid-crystal phase transition temperature of the composition is preferably within a range of from 10 to 250° C. from the viewpoint of the production aptitude and the like thereof, more preferably from 10 to 150° C. When the temperature is lower than 10° C., then the production method would require a cooling step or the like for cooling the coating film to a temperature falling within the range within which the coating film could exhibit a liquid-crystal phase. On the other hand, when the transition temperature is higher than 200° C., then the production method would require a high temperature in order that the coating film could be once in an isotropic liquid state at a further higher temperature than in the temperature range within which the film could exhibit a liquid-crystal phase; however, this is disadvantageous in point of waste of thermal energy, substrate deformation, degradation, etc.

Next, in the step (ii), the coating film in the state of a liquid-crystal phase is cured. For curing, any polymerization method is employable, including a radical polymerization method, an anionic polymerization method, a cationic polymerization method, a coordination polymerization method, etc. A suitable polymerization method will be selected in accordance with the compound of the formula (I) or (I′). The polymerization gives a polymer that has a unit derived from the compound of the formula (I) or (I′) in the constitutive units therein.

In one example, the curing reaction is attained through UV irradiation. For UV irradiation, usable is a light source of a UV lamp, etc. In this step, UV irradiation promotes curing of the composition to fix the cholesteric liquid-crystal phase, and a cured film is thereby formed.

The UV irradiation energy dose is not specifically defined, but is, in general, preferably from 100 mJ/cm² to 800 mJ/cm² or so. The time for UV irradiation for the coating film is not specifically defined, and the time will be determined from the viewpoint of both sufficient strength and productivity of the cured film.

For promoting the curing reaction, the UV irradiation may be attained under heat. The temperature in UV irradiation is preferably within a temperature range within which the coating film could exhibit a liquid-crystal phase in order that the liquid-crystal phase of the film could be prevented from being disordered. The oxygen concentration in the atmosphere during the process may participate in the degree of polymerization, and therefore, in case where the desired degree of polymerization could not be attained in air and the film strength is insufficient, it is desirable that the oxygen concentration in the atmosphere is lowered according to a nitrogen purging method or the like.

In the above-mentioned step, the liquid-crystal phase is fixed to form a cured film. Regarding the “fixed” state of liquid-crystal phase in this, the most typical and preferred embodiment of the state is such that the alignment of the compound in a liquid-crystal phase is maintained as such. However, the invention is not limited to the case. Concretely, the fixed state means that, in a temperature range of from 0° C. to 50° C. in an ordinary condition, or in a temperature range of from −30° C. to 70° C. in a severe condition, the layer has no flowability and the alignment morphology in the layer is not changed by any external field or external force applied thereto, and in that condition, the layer can continue to stably keep the fixed alignment morphology therein. In the invention, owing to the curing reaction to be promoted through UV irradiation, the alignment state of the liquid-crystal phase is fixed in the cured film.

In the invention, it is enough that the optical properties of the liquid-crystal phase are kept in the layer, and finally it is unnecessary that the composition in the cured film would exhibit liquid crystallinity. For example, the composition may lose liquid crystallinity through the curing reaction for polymerization.

The thickness of the cured film is not specifically defined. Depending on the use thereof or in accordance with the desired optical characteristics thereof, the preferred thickness of the film will be determined. In general, the thickness is preferably from 0.05 to 50 μm, more preferably from 1 to 35 μm.

(2) Substrate

The film of the invention may have a substrate. The substrate may be any self-supporting one capable of supporting the above-mentioned cured film, and is not specifically defined in point of the material and the optical characteristics thereof. The substrate may be selected from glass plates, quartz plates, polymer films, etc. Depending on the use thereof, the substrate may be required to have high transparency to UV light. As the polymer film having high transparency to visible light, there are mentioned various types of polymer films for optical films to be used as constituent parts of display devices such as liquid-crystal display devices, etc. The substrate includes, for example, polyester films of polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate (PEN), etc.; polycarbonate (PC) films, polymethyl methacrylate films; polyolefin films of polyethylene, polypropylene, etc.; polyimide films, triacetyl cellulose (TAC) films, etc. Preferred are polyethylene terephthalate and triacetyl cellulose.

(3) Alignment Layer

The film of the invention may have an alignment layer between the substrate and the above-mentioned cured film. The alignment layer has the function of more accurately defining the alignment direction of the liquid-crystal compound in the cured film. The alignment layer may be provided by means of rubbing treatment of an organic compound (preferably a polymer), oblique vapor deposition of an inorganic compound, formation of a layer having microgrooves, etc. Further known is an alignment layer capable of exhibiting the alignment function through electric field impartation, magnetic field impartation or photoirradiation. Preferably, the alignment layer is formed through rubbing treatment of the surface of a polymer film.

Preferably, the material of the alignment layer is a polymer of an organic compound, for which a self-crosslinkable polymer or a polymer crosslinkable by a crosslinking agent is well used. Naturally, a polymer having the two functions is also usable. Examples of the polymer include polymethyl methacrylate, acrylic acid/methacrylic acid copolymer, styrene/maleinimide copolymer, polyvinyl alcohol and modified polyvinyl alcohol, poly(N-methylolacrylamide), styrene/vinyltoluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, polyolefin chloride, polyester, polyimide, vinyl acetate/vinyl chloride copolymer, ethylene/vinyl acetate copolymer, carboxymethyl cellulose, gelatin, polyethylene, polypropylene, polycarbonate and other polymers, as well as other compounds such as silane coupling agents, etc. Preferred examples of the polymer are water-soluble polymers such as poly(N-methylolacrylamide), carboxymethyl cellulose, gelatin, polyvinyl alcohol and modified polyvinyl alcohol, etc. More preferred are gelatin, polyvinyl alcohol and modified polyvinyl alcohol; and more preferred are polyvinyl alcohol and modified polyvinyl alcohol.

(4) Use of Film of the Invention

One embodiment of the film of the invention is a film which is produced by fixing the alignment of the liquid-crystal phase (for example, horizontal alignment, vertical alignment, hybrid alignment, etc.) of the composition of the invention and which shows optical anisotropy. The film is utilized as an optical compensatory film or the like in liquid-crystal display devices, etc.

One embodiment of the film of the invention is a film which is produced by fixing the cholesteric liquid-crystal phase of the polymerizable composition of the invention and which exhibits selective reflection characteristics against a light falling within a predetermined wavelength range. In the cholesteric liquid-crystal phase, the liquid-crystal molecules are aligned helically. The film that exhibits selective reflection characteristics within the IR wavelength range (having a wavelength of from 800 to 1300 nm) may be, for example, stuck to windowpanes of buildings or vehicles or may be incorporated in laminated glass and may be thereby used as a heat-insulating member therein.

In addition, the film of the invention can be utilized in many applications for polarizing elements, selective reflection films, color filters, antireflection films, viewing angle compensation films, holography, alignment films and others that are constituent elements of optical devices.

3. Polymer

The invention also relates to a polymer produced by polymerizing one or more polymerizing compounds of the above-mentioned formula (I) or (I′), and to a polymer produced by polymerizing the polymerizable composition of the invention. The polymer may be a liquid-crystalline one or non-liquid-crystalline one. As containing the recurring unit derived from the polymerizing compound of the formula (I) or (I′), the polymer shows a high Δn and is useful as a material for various optical elements.

EXAMPLES

The characteristics of the invention are described more concretely with reference to Examples and Comparative Examples given below (however, Comparative Examples are not always known techniques). In the following Examples, the material used, its amount and ratio, the details of the treatment and the treatment process may be suitably modified or changed not overstepping the spirit and the scope of the invention. Accordingly, the scope of the invention should not be limitatively interpreted by the Examples mentioned below.

1. Synthesis Examples and Physical Data of Compounds of Formula (I) Synthesis of Exemplary Compound (I-1):

(1) 12.4 g (50 mmol) of 4-acryloyloxybenzaldehyde was added to a three-neck flask to which 0.30 g of 2,6-di-t-butyl-4-methylphenol and 20 ml of toluene had been added. In a nitrogen atmosphere, the inner temperature was raised up to 40° C., and then 6.2 g (50 mmol) of 4-amino-m-cresol was added thereto. Subsequently, this was refluxed for 2 hours, and then water and toluene were completely evaporated away with a Dean Stark apparatus to give a brown oily substance. The oily substance was completely dissolved in 30 ml of THF (this is solution A).

(2) Separately, 4.3 ml (55 mmol) of MsCl and 10 ml of THF were added to a three-neck flask, and immersed in an ice/methanol bath so that the inner temperature was made −5° C. While its inner temperature was kept at 5° C. or lower, a mixed solution of 4-acryloyloxycinnamic acid (14.5 g, 50 mmol)/diisopropylethylamine (hereinafter referred to as DIPEA, 9.6 ml, 55 mmol)/2,6-di-t-butyl-4-methylphenol (0.30 g)/THF (30 ml) was dropwise added to the above solution. While kept at 5° C. or lower, this solution was stirred for 2 hours, and then 9.6 ml (55 mmol) of DIPEA, 0.15 g of DMAP and the solution A prepared in (1) were added thereto in that order (whereupon the inner temperature was kept at 5° C. or lower). The reaction temperature was elevated up to 25° C., and the reaction mixture was stirred for 2 hours and then quenched with 10 ml of methanol added thereto. This was processed for liquid-liquid separation with ethyl acetate/pure water added thereto, and the organic layer was dried with sodium sulfate and then concentrated to give a brown oily substance. The oily substance was concentrated through a column of ethyl acetate/hexane, and recrystallized with methanol to give 6.3 g (yield 20%) of a white solid, compound (I-1).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 2.4 (s, 3H), 4.1 (m, 4H), 4.3 (m, 4H), 5.8 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 6.5 (d, 1H), 6.9-7.1 (m, 7H), 7.5 (d, 2H), 7.8 (d×2, 3H), 8.3 (s, 1H).

Synthesis of Exemplary Compound (I-2):

This was synthesized according to the same method as that for the exemplary compound (I-1) except that 4-amino-3-chlorophenol was used in place of 4-amino-m-cresol. The yield was 5.8 g (18%).

1H-NMR (DMSO): δ=1.8-2.0 (brs, 8H), 4.0 (m, 4H), 4.2 (m, 4H), 5.9 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 6.7 (d, 1H), 7.0 (d, 2H), 7.1 (d, 2H), 7.2 (d, 1H), 7.3 (d, 1H), 7.4 (s, 1H), 7.7 (d, 2H), 7.8 (d, 1H), 7.9 (d, 2H), 8.5 (s, 1H).

Synthesis of Exemplary Compound (I-7):

This was synthesized according to the same method as that for the exemplary compound (I-1) except that 4-amino-o-cresol was used in place of 4-amino-m-cresol. The yield was 5.9 g (19%).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 2.3 (s, 3H), 4.1 (m, 4H), 4.3 (m, 4H), 5.8 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 6.5 (d, 1H), 7.0 (d×2, 4H), 7.1 (m, 3H), 7.5 (d, 2H), 7.8 (m, 3H), 8.4 (s, 1H).

Synthesis of Exemplary Compound (I-8):

This was synthesized according to the same method as that for the exemplary compound (I-1) except that 4-aminophenol was used in place of 4-amino-m-cresol. The yield was 9.5 g (31%).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 4.1 (m, 4H), 4.3 (m, 4H), 5.8 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 6.5 (s, 1H), 7.0 (d×2, 4H), 7.0 (d×2, 4H), 7.5 (d, 2H), 7.8 (d×2, 3H), 8.4 (s, 1H).

Synthesis of Exemplary Compound (II-1):

This was synthesized according to the same method as that for the exemplary compound (I-1) except that 4-aminophenol was used in place of 4-amino-m-cresol and that 4-acryloyloxybenzoic acid was used in place of 4-acryloyloxycinnamic acid. The yield was 5.6 g (19%).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 4.1 (m, 4H), 4.3 (m, 4H), 5.8 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 7.0 (d×2, 4H), 7.3 (d×2, 4H), 7.8 (d, 2H), 8.2 (d, 2H), 8.4 (s, 1H).

Physical Properties of Compounds of Formula (I):

Δn of the compounds synthesized in the above was directly measured according to the method described in Liquid Crystal Handbook (by Liquid Crystal Handbook Editorial Committee), p. 202. Concretely, each compound synthesized in the above was injected into a wedge-shaped cell, this was irradiated with a laser light at a wavelength of 550 nm, and the refraction angle of the transmitted light was measured to determine Δn of the compound.

The following Table shows Δn of each compound, the phase transition temperature thereof as measured through texture observation with a polarizing microscope, and the color of the crystal. As Comparative Examples, Δn, the phase transition temperature and the color of the solid of the following compounds (R-1) to (R-3) for Comparative Compounds are also shown therein. In addition, the absorption spectra of the series of the compounds are shown in FIG. 1 and FIG. 2. The graphs of FIG. 2 are partly-enlarged graphs of the graphs of FIG. 1.

(R-1) is a monoazomethine compound, in which, however, the side chain to link the polymerizable group and the mesogen therein is short; (R-2) is a bisazomethine compound; and (R-3) is a liquid-crystal compound not containing an azomethine group.

TABLE 1 Tested Phase Transition Compound Temperature Δn Color Example 1 Compound Cr 80 N 167 Iso 0.286 (70° C.) white (I-1) Example 2 Compound Cr 84 N 164 Iso 0.276 (70° C.) white (I-2) Example 3 Compound Cr 80 N 167 Iso 0.276 (70° C.) white (I-7) Example 4 Compound Cr 76 Sc 112 N 0.285 (100° C.) white (I-8) 209 Iso Example 5 Compound Cr 111 N 179 Iso immeasurable white (II-1) as crystallized Comparative Compound Cr 77 N 118 Iso 0.239 (70° C.) white Example 1 R-1 Comparative Compound Cr 79 N 145 Iso 0.319 (70° C.) yellow Example 2 R-2 Comparative Compound Cr 80 N 124 Iso 0.162 (70° C.) white Example 3 R-3

From the results shown in the above Table, it is understood that the compounds of the formula (I) all have a high Δn as compared with the monoazomethine-type polymerizing liquid-crystal compound (R-1) falling outside the scope of the formula (I) and the liquid-crystal compound (R-3) not containing an azomethine group.

The exemplary compound (II-1) crystallized at 70° C., and therefore its Δn at 70° C. could not be measured. In general, Δn tends to increase when the temperature lowers. The relationship between the temperature and Δn of the compound (II-1) is near to primary correlation, and coming from extrapolation, Δn of the compound is 0.25 at 70° C.

From the absorption spectrum curves shown in FIG. 1 and FIG. 2, it is understood that the bisazomethine-type polymerizing liquid crystal (R-2) that has heretofore been known has an absorption at a wavelength of 400 nm or more and is therefore yellowish, but that the absorption at a wavelength of 400 nm or more by the monoazomethine compounds of the formula (I) in the invention is small and therefore the compounds are white.

2. Production and Evaluation of Retardation Films (Examples 6 to 10, Comparative Examples 4 and 5) Example 6

Using the exemplary compound (I-1) of the formula (I) in the invention that had been synthesized in the above, a liquid-crystal composition coating liquid (1) comprising the following ingredients was prepared.

Exemplary Compound (I-1) 100 parts by mass Air-Interface Alignment Agent (1) 0.1 parts by mass Polymerization Initiator IRGACURE 819 (by 3 parts by mass Ciba Japan) Solvent, chloroform 800 parts by mass

Air-Interface Alignment Agent (1)

Next, a polyimide alignment film material, Nissan Chemical's SE-130 was applied onto a washed glass substrate according to a spin coating method, dried and then fired at 250° C. for 1 hour. This was rubbed to produce an alignment film-having substrate. Onto the rubbed surface of the alignment film of the substrate, the liquid-crystal composition coating liquid (1) was applied at room temperature according to a spin coating method, then ripened for alignment at 120° C. for 30 seconds, and thereafter photoirradiated with a high-pressure mercury lamp, from which the short-wavelength UV ingredient had been removed, in a nitrogen gas atmosphere at room temperature for 10 seconds for alignment fixation to thereby form a retardation film of Example 6. During the period after coating and before heating, the coating film did not crystallize.

The obtained retardation film was observed with a polarizing microscope, which confirmed uniform monoaxial orientation with no orientation defect in the film.

Further, the film was analyzed with AXOMETRIX's AxoScan in a tip-tilt mode. As a result, the mean tilt angle of the liquid crystal, as computed by this apparatus, was 1 degree, and this confirmed the formation of an A-plate-type retardation film.

As computed from the retardation measured by the use of the above apparatus and from the thickness of the retardation film measured by the use of a confocal laser thickness meter (Keyence's FV-7510), Δn at a wavelength of 550 nm was 0.235.

Examples 7 to 10

Liquid-crystal composition coating liquids were prepared in the same manner as above except that the compounds synthesized in the above were used in place of the exemplary compound (I-1). Using the coating liquids and in the same manner as in Example 6, retardation films of Examples 7 to 10 were formed.

These retardation films all exhibited good orientation performance and had a low haze of at most 0.1. The data of Δn of the retardation films, as determined in the same manner as in Example 6, are collectively shown in the following Table.

Comparative Example 4

A liquid-crystal composition coating liquid (2) comprising the following ingredients was prepared in the same manner as in Example 6.

Polymerizing Liquid-Crystal Compound (R-1) 100 parts by mass mentioned above Air-Interface Alignment Agent (1) 0.1 parts by mass Polymerization Initiator IRGACURE 819 (by 3 parts by mass Ciba Japan) Solvent, chloroform 800 parts by mass

A retardation film of Comparative Example 4 was formed in the same manner as in Example 6 except that the liquid-crystal composition coating liquid (2) was used in place of the liquid-crystal composition coating liquid (1). However, since the liquid crystal uppermost temperature of the polymerizable composition was lower than that of the exemplary compound (I-5), the temperature for alignment ripening in this case was 90° C. During the period after coating and before heating, a liquid crystal partly deposited on the coating film. Accordingly, even after this was reheated and further processed for alignment ripening, some thickness unevenness still remained in the crystal-deposited part of the film.

As measured according to the same method as in Example 6, Δn at a wavelength of 550 nm of the retardation film of Comparative Example 4 was 0.256, and the haze thereof was 0.18.

Comparative Example 5

A liquid-crystal composition coating liquid (3) comprising the following ingredients was prepared in the same manner as in Example 6.

Polymerizing Liquid-Crystal Compound (R-2) 100 parts by mass mentioned above Air-Interface Alignment Agent (1) 0.1 parts by mass Polymerization Initiator IRGACURE 819 (by 3 parts by mass Ciba Japan) Solvent, chloroform 800 parts by mass

A retardation film of Comparative Example 5 was formed in the same manner as in Example 6 except that the liquid-crystal composition coating liquid (3) was used in place of the liquid-crystal composition coating liquid (1). However, since the liquid crystal uppermost temperature of the polymerizable composition was lower than that of the exemplary compound (I-5), the temperature for alignment ripening in this case was 90° C. During the period after coating and before heating, a liquid crystal partly deposited on the coating film. Accordingly, even after this was reheated and further processed for alignment ripening, some thickness unevenness still remained in the crystal-deposited part of the film.

As measured according to the same method as in Example 6, Δn at a wavelength of 550 nm of the retardation film of Comparative Example 5 was 0.360, and the haze thereof was 0.13.

The above results are shown in the following Table.

TABLE 2 Tested Compound Δn Haze Color Example 6 Compound (I-1) 0.320 0.08 white Example 7 Compound (I-2) 0.309 0.09 white Example 8 Compound (I-7) 0.327 0.06 white Example 9 Compound (I-8) 0.270 0.07 white Example 10 Compound (II-1) 0.262 0.07 white Comparative Compound R-1 0.256 0.18 white Example 4 Comparative Compound R-2 0.360 0.13 yellow Example 5

From the results shown in the above Table, it is understood that the retardation films formed by the use of the compound of the general formula (I) in the invention have a large Δn and a small haze as compared with the retardation film formed by the use of the conventional, monoazomethine-type polymerizing liquid-crystal compound (R-1). In addition, it is also understood that, while the film formed by the use of the conventional, bis-Schiff-type polymerizing liquid-crystal compound (R-2) is yellow, the retardation films of Examples of the invention are all white and have a small haze.

3. Production and Evaluation of Selective Reflection Films (Examples 11 to 15, Comparative Examples 6 and 7)

Using the exemplary compound (I-1) of the formula (I) in the invention, as synthesized in the above, a liquid-crystal composition coating liquid (4) comprising the following ingredients was prepared.

Exemplary Compound (I-1) 33 parts by mass Polymerizing Liquid-Crystal Compound (R-3) 67 parts by mass Chiral Agent, Paliocolor LC756 (by BASF) 3 parts by mass Air-Interface Alignment Agent (1) 0.04 parts by mass Polymerization Initiator IRGACURE 819 (by 3 parts by mass Ciba Japan) Solvent, chloroform 300 parts by mass

The liquid-crystal composition coating liquid (4) was applied onto the surface of the alignment film of the alignment film-having substrate as produced in the same manner as in Example 6, according to a spin coating method at room temperature, then heated at 120° C. for 3 minutes for alignment ripening, and thereafter photoirradiated with a high-pressure mercury lamp, from which the short-wavelength UV ingredient had been removed, in a nitrogen gas atmosphere at room temperature for 10 seconds for alignment fixation to thereby produce a selective reflection film of Example 11. During the period after coating and before heating, the coating film did not crystallize.

The obtained selective reflection film was observed with a polarizing microscope, which confirmed uniform monoaxial orientation with no orientation defect in the film. Further, the transmission spectrum of the film was measured with a spectrophotometer, Shimadzu's UV-3100PC, and the spectrum had a selective reflection peak in the IR region having a center at 1000 nm and the half-value width of the peak was 146 nm. As computed from the peak half-value width and the helical period of the polymerizable composition, Δn at a wavelength of 1000 nm was 0.232. The haze, as measured with a haze meter, Nippon Denshoku's NHD2000, was 0.07.

Examples 12 to 15

Liquid-crystal composition coating liquids were prepared in the same manner as in Example 11 except that the exemplary compounds synthesized in the above were used in place of the exemplary compound (I-1). Using the coating liquids and in the same manner as in Example 11, selective reflection films of Examples 12 to 15 were produced. These selective reflection films all exhibited good orientation. As similarly determined, the peak half-value width of the selective reflection films and Δn thereof obtained from the former are collectively shown in the following Table.

Comparative Example 6

In the same manner as in Example 11, a liquid-crystal composition coating liquid (5) comprising the following ingredients was prepared.

Polymerizing Liquid-Crystal Compound (R-1) 33 parts by mass Polymerizing Liquid-Crystal Compound (R-3) 67 parts by mass Chiral Agent, Paliocolor LC756 (by BASF) 2.8 parts by mass Air-Interface Alignment Agent (1) 0.04 parts by mass Polymerization Initiator IRGACURE 819 (by 3 parts by mass Ciba Japan) Solvent, chloroform 300 parts by mass

A selective reflection film of Comparative Example 6 was produced in the same manner as in Example 11 except that the liquid-crystal composition coating liquid (5) was used in place of the liquid-crystal composition coating liquid (4). However, since the liquid crystal uppermost temperature of the polymerizable composition was lower than that of the composition used in Example 11, the temperature for alignment ripening in this case was 90° C. During the period after coating and before heating, a liquid crystal partly deposited on the coating film. Accordingly, even after this was reheated and further processed for alignment ripening, some thickness unevenness and orientation unevenness still remained in the crystal-deposited part of the film.

The obtained selective reflection film of Comparative Example 6 had a selective reflection peak in the IR region having a center at around 1000 nm and the half-value width of the peak was 120 nm. As computed from the peak half-value width and the helical period of the polymerizable composition, Δn at a wavelength of 1000 nm was 0.190.

Comparative Example 7

In the same manner as in Example 11, a liquid-crystal composition coating liquid (6) comprising the following ingredients was prepared.

Polymerizing Liquid-Crystal Compound (R-2) 33 parts by mass Polymerizing Liquid-Crystal Compound (R-3) 67 parts by mass Chiral Agent, Paliocolor LC756 (by BASF) 2.8 parts by mass Air-Interface Alignment Agent (1) 0.04 parts by mass Polymerization Initiator IRGACURE 819 (by 3 parts by mass Ciba Japan) Solvent, chloroform 300 parts by mass

A selective reflection film of Comparative Example 7 was produced in the same manner as in Example 11 except that the liquid-crystal composition coating liquid (6) was used in place of the liquid-crystal composition coating liquid (4).

The selective reflection film had a selective reflection peak in the IR region having a center at around 1000 nm and the half-value width of the peak was 154 nm. As computed from the peak half-value width and the helical period of the polymerizable composition, Δn at a wavelength of 1000 nm was 0.243. The film was yellow.

The above results are shown in the following Table.

TABLE 3 Tested Half-Value Compound Δn Haze Width Color Example 11 Compound 0.235 0.07 148 white (I-1) Example 12 Compound 0.224 0.06 141 white (I-2) Example 13 Compound 0.224 0.08 141 white (I-7) Example 14 Compound 0.230 0.09 145 white (I-8) Example 15 Compound 0.199 0.09 125 white (II-1) Comparative Compound R-1 0.190 0.18 120 white Example 6 Comparative Compound R-2 0.243 0.15 154 yellow Example 7

From the results shown in the above Table, it is understood that the selective reflection films produced by the use of the compounds of the general formula (I) in the invention have a larger Δn and have a broader selective reflection range, as compared with the selective reflection film produced by the use of the conventional, monoazomethine polymerizing liquid-crystal compound (R-1). Further, it is also understood that, while the film produced by the use of the conventional, bisazomethine polymerizing liquid crystal (R-2) is yellow, the selective reflection films of Examples of the invention are all colorless.

4. Synthesis Examples and Physical Data of Compounds of Formula (I′) Synthesis of Exemplary Compound (I′-2):

(1) 7.32 g (60 mmol) of 4-hydroxybenzaldehyde was added to a three-neck flask to which 30 ml of toluene had been added. In a nitrogen atmosphere, the inner temperature was raised up to 40° C., and then 11.3 g (60 mmol) of 4-amino-o-bromophenol was added thereto. Subsequently, this was refluxed for 2 hours, and then water and toluene were completely evaporated away with a Dean Stark apparatus to give a yellow solid. The solid was completely dissolved in 50 ml of THF (this is solution A).

(2) Separately, 10.2 ml (132 mmol) of MsCl and 20 ml of THF were added to a three-neck flask, and immersed in an ice/methanol bath so that the inner temperature was made −5° C. While its inner temperature was kept at 5° C. or lower, a mixed solution of 4-acryloyloxybenzoic acid (31.7 g, 120 mmol)/diisopropylethylamine (hereinafter referred to as DIPEA, 26.1 ml, 150 mmol)/2,6-di-t-butyl-4-methylphenol (0.30 g)/THF (70 ml) was dropwise added to the above solution. While kept at 5° C. or lower, this solution was stirred for 2 hours, and then 26.1 ml (150 mmol) of DIPEA, 0.15 g of DMAP and the solution A prepared in (1) were added thereto in that order (whereupon the inner temperature was kept at 5° C. or lower). The reaction temperature was elevated up to 25° C., and the reaction mixture was stirred for 2 hours and then quenched with 10 ml of methanol added thereto. This was processed for liquid-liquid separation with ethyl acetate/pure water added thereto, and the organic layer was dried with sodium sulfate and then concentrated to give a crude crystal. The crystal was recrystallized with ethyl acetate/methanol to give 29.7 g (yield 63%) of a white solid, compound (I′-2).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 4.1 (brs, 4H), 4.3 (brs, 4H), 5.8 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 7.0 (d×2, 4H), 7.2-7.3 (d×3, 6H), 7.5 (s, 1H), 8.0 (d, 2H), 8.2 (d×2, 4H), 8.5 (s, 1H).

Synthesis of Exemplary Compound (I′-5):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-amino-m-cresol was used in place of 4-amino-o-bromophenol. The yield was 28.9 g (67%).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 2.4 (s, 3H), 4.0-4.1 (m, 4H), 4.2-4.3 (m, 4H), 5.8 (d, 2H), 6.2 (dd, 2H), 6.4 (d, 2H), 6.9-7.1 (d, 7H), 7.3-7.4 (d, 2H), 8.0 (d, 2H), 8.1 (m, 4H), 8.4 (s, 1H).

Synthesis of Exemplary Compound (I′-6):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-amino-3-chlorophenol was used in place of 4-amino-o-bromophenol. The yield was 26.6 g (60%).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 4.0-4.2 (brs, 4H), 4.2-4.3 (brs, 4H), 5.8 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 7.0 (d, 4H), 7.1 (d, 1H), 7.2 (d, 1H), 7.3 (m, 3H), 8.0 (d, 2H), 8.1 (d×2, 4H), 8.4 (s, 1H).

Synthesis of Exemplary Compound (I′-4):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-amino-3-methoxyphenol was used in place of 4-amino-o-bromophenol. The yield was 25.6 g (58%).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 3.9 (s, 3H), 4.1 (brs, 4H), 4.3 (brs, 4H), 5.8 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 6.8 (d, 2H), 7.0 (d, 4H), 7.1 (d, 1H), 7.3 (d, 2H), 8.0 (d, 2H), 8.2 (d, 4H), 8.5 (s, 1H).

Synthesis of Exemplary Compound (I′-3):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-amino-2-chlorophenol was used in place of 4-amino-o-bromophenol. The yield was 28.0 g (63%).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 4.1 (brs, 4H), 4.3 (brs, 4H), 5.8 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 7.0 (d, 4H), 7.2 (d, 1H), 7.3 (m, 4H), 8.0 (d, 2H), 8.2 (d×2, 4H), 8.5 (s, 1H).

Synthesis of Exemplary Compound (I′-1):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-amino-o-cresol was used in place of 4-amino-o-bromophenol. The yield was 30.7 g (71%).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 2.3 (s, 3H), 4.1 (brs, 4H), 4.3 (brs, 4H), 5.8 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 7.0 (d, 4H), 7.1-7.2 (m, 3H), 7.3 (d, 2H), 8.0 (d, 2H), 8.2 (d, 4H), 8.5 (s, 1H).

Synthesis of Exemplary Compound (I′-9):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-aminophenol was used in place of 4-amino-o-bromophenol and that vanillin was used in place of 4-hydroxybenzaldehyde. The yield was 28.7 g (65%).

1H-NMR (DMSO): δ=1.7-1.9 (brs, 8H), 3.8 (s, 3H), 4.1-4.3 (m, 8H), 5.9 (d, 2H), 6.2 (dd, 2H), 6.3 (d, 2H), 7.1 (d, 4H), 7.3-7.4 (d×2, 5H), 7.6 (d, 1H), 7.7 (s, 1H), 8.1 (m, 4H), 8.7 (s, 1H).

Synthesis of Exemplary Compound (I′-13):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-amino-3-bromophenol was used in place of 4-amino-o-bromophenol and that vanillin was used in place of 4-hydroxybenzaldehyde. The yield was 30.3 g (62%).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 3.9 (s, 3H), 4.1 (brs, 4H), 4.3 (brs, 4H), 5.8 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 7.0 (d, 4H), 7.1 (d, 1H), 7.2 (d, 1H), 7.3 (d, 1H), 7.4 (d, 1H), 7.5 (s, 1H), 7.8 (s, 1H), 8.2 (d, 4H), 8.5 (s, 1H).

Synthesis of Exemplary Compound (I′-15):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-amino-m-cresol was used in place of 4-amino-o-bromophenol and that vanillin was used in place of 4-hydroxybenzaldehyde. The yield was 26.5 g (59%).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 2.4 (s, 3H), 3.9 (s, 3H), 4.1 (m, 4H), 4.3 (m, 4H), 5.8 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 7.0 (d×2, 4H), 7.1 (m, 3H), 7.4 (d, 1H), 7.7 (s, 1H), 8.2 (d×2, 4H), 8.4 (s, 1H).

Synthesis of Exemplary Compound (II′-1):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-amino-m-cresol was used in place of 4-amino-o-bromophenol and that 4-hydroxyacetophenone was used in place of 4-hydroxybenzaldehyde. The yield was 25.5 g (58%).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 2.1 (s, 3H), 2.3 (s, 3H), 4.1 (brs, 4H), 4.3 (brs, 4H), 5.8 (d, 2H), 6.2 (dd, 2H), 6.4 (d, 2H), 6.7 (d, 1H), 6.9-7.1 (m, 6H), 7.3-7.4 (d, 2H), 8.0-8.3 (m, 6H).

Synthesis of Exemplary Compound (I′-7):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-amino-2-methoxycarbonylphenol was used in place of 4-amino-o-bromophenol. The yield was 27.5 g (60%).

1H-NMR (CDCl₃): δ=1.8-2.0 (brs, 8H), 3.7 (s, 3H), 4.1 (brs, 4H), 4.3 (brs, 4H), 5.8 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 7.0 (d, 4H), 7.3 (d, 2H), 7.5 (d, 1H), 7.9 (s, 1H), 8.0 (d, 2H), 8.2 (d, 4H), 8.5 (s, 1H).

Synthesis of Exemplary Compound (I′-12):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-amino-2,6-dichlorophenol was used in place of 4-amino-o-bromophenol. The yield was 28.4 g (61%).

1H-NMR (DMSO): δ=1.8-2.0 (brs, 8H), 4.1-4.3 (brs, 8H), 5.9 (d, 2H), 6.2 (dd, 2H), 6.4 (d, 2H), 7.1 (d×2, 4H), 7.4 (d, 2H), 7.6 (s×2, 2H), 8.0-8.2 (d×3, 6H), 8.8 (s, 1H).

Synthesis of Exemplary Compound (I′-10):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-amino-2,5-dichlorophenol was used in place of 4-amino-o-bromophenol. The yield was 29.7 g (64%).

1H-NMR (DMSO): δ=1.8-2.0 (brs, 8H), 4.1-4.3 (brs, 8H), 5.9 (d, 2H), 6.2 (dd, 2H), 6.3 (d, 2H), 7.1 (d×2, 4H), 7.5 (d, 2H), 7.7 (s, 1H), 7.8 (s, 1H), 8.0-8.2 (m, 6H), 8.7 (s, 1H).

Synthesis of Exemplary Compound (I′-11):

This was synthesized according to the same method as that for the exemplary compound (I′-2) except that 4-amino-2,5-dimethylphenol was used in place of 4-amino-o-bromophenol. The yield was 29.5 g (62%).

1H-NMR (DMSO): δ=1.8-2.0 (brs, 8H), 2.1 (s, 3H), 2.3 (s, 3H), 4.0-4.2 (brs, 8H), 5.9 (d, 2H), 6.2 (dd, 2H), 6.3 (d, 2H), 7.1 (d, 2H), 7.2 (d×2, 4H), 7.4 (d, 2H), 8.0-8.2 (m, 6H), 8.6 (s, 1H).

Physical Properties of Compounds of Formula (I′):

Δn of the compounds synthesized in the above was directly measured according to the method described in Liquid Crystal Handbook (by Liquid Crystal Handbook Editorial Committee), p. 202. Concretely, each compound synthesized in the above was injected into a wedge-shaped cell, this was irradiated with a laser light at a wavelength of 550 nm, and the refraction angle of the transmitted light was measured to determine Δn of the compound.

The following Table shows Δn of each compound, the phase transition temperature thereof as measured through texture observation with a polarizing microscope, and the color of the crystal. As Comparative Examples, Δn, the phase transition temperature and the color of the solid of the following compounds (R-1) to (R-3) for Comparative Compounds are also shown therein. The temperature in the column of “Δn” in the following Table means the measured temperature. In addition, the absorption spectra of the series of the compounds are shown in FIG. 3 and FIG. 4. The graphs of FIG. 4 are partly-enlarged graphs of the graphs of FIG. 3.

(R-1) is a monoazomethine compound, in which, however, the side chain to link the polymerizable group and the mesogen therein is short; (R-2) is a bisazomethine compound; and (R-3) is a liquid-crystal compound not containing an azomethine group.

TABLE 4 Tested Phase Transition Compound Temperature Δn Color Example 16 Compound Cr 80 N 250° C. 0.252 (70° C.) white (I′-2) or more Iso Example 17 Compound Cr 120 N 255 Iso 0.258 (70° C.) white (I′-5) Example 18 Compound Cr 111 N 250° C. 0.256 (70° C.) white (I′-6) or more Iso Example 19 Compound Cr 115 N 210 Iso 0.249 (70° C.) white (I′-4) Example 20 Compound Cr 91 N 250° C. 0.262 (70° C.) white (I′-3) or more Iso Example 21 Compound Cr 92 N 250° C. 0.259 (70° C.) white (I′-1) or more Iso Example 22 Compound Cr 98 N 228 Iso 0.257 (70° C.) white (I′-9) Example 23 Compound Cr 102 N 192 Iso 0.230 (70° C.) white (I′-13) Example 24 Compound Cr 97 N 201 Iso 0.240 (70° C.) white (I′-15) Example 25 Compound Cr 106 N 223 Iso immeasurable white (II′-1) as crystallized Example 26 Compound Cr 67 N 232 Iso 0.258 (70° C.) white (I′-7) Example 27 Compound Cr 95 N 217 Iso 0.255 (70° C.) white (I′-12) Example 28 Compound Cr 78 N 227 Iso 0.251 (70° C.) white (I′-10) Example 29 Compound Cr 87 N 221 Iso 0.240 (70° C.) white (I′-11) Comparative Compound Cr 77 N 118 Iso 0.239 (70° C.) white Example 1 R-1 Comparative Compound Cr 79 N 145 Iso 0.319 (70° C.) yellow Example 2 R-2 Comparative Compound Cr 80 N 124 Iso 0.162 (70° C.) white Example 3 R-3

From the results shown in the above Table, it is understood that the compounds of the formula (I′) all have a high Δn as compared with the monoazomethine-type polymerizing liquid-crystal compound (R-1) falling outside the scope of the formula (I′) and the liquid-crystal compound (R-3) not containing an azomethine group. From the absorption spectrum curves shown in FIG. 3 and FIG. 4, it is understood that the bisazomethine-type polymerizing liquid crystal (R-2) that has heretofore been known in the art has an absorption at a wavelength of 400 nm or more and is therefore yellowish, but that the absorption at a wavelength of 400 nm or more by the monoazomethine compounds of the formula (I′) in the invention is small and therefore the compounds are white.

5. Production and Evaluation of Retardation Films (Examples 30 to 43) Example 30

Using the exemplary compound I-2 of the formula (I′) in the invention that had been synthesized in the above, a liquid-crystal composition coating liquid (1) comprising the following ingredients was prepared.

Exemplary Compound (I′-2) 100 parts by mass Air-Interface Alignment Agent (1) 0.1 parts by mass Polymerization Initiator IRGACURE 819 (by 3 parts by mass Ciba Japan) Solvent, chloroform 800 parts by mass

Air-Interface Alignment Agent (1)

Next, a polyimide alignment film material, Nissan Chemical's SE-130 was applied onto a washed glass substrate according to a spin coating method, dried and then fired at 250° C. for 1 hour. This was rubbed to produce an alignment film-having substrate. Onto the rubbed surface of the alignment film of the substrate, the liquid-crystal composition coating liquid (1) was applied at room temperature according to a spin coating method, then ripened for alignment at 120° C. for 30 seconds, and thereafter photoirradiated with a high-pressure mercury lamp, from which the short-wavelength UV ingredient had been removed, in a nitrogen gas atmosphere at room temperature for 10 seconds for alignment fixation to thereby produce a retardation film of Example 30. During the period after coating and before heating, the coating film did not crystallize.

The obtained retardation film was observed with a polarizing microscope, which confirmed uniform monoaxial orientation with no orientation defect in the film.

Further, the film was analyzed with AXOMETRIX's AxoScan in a tip-tilt mode. As a result, the mean tilt angle of the liquid crystal, as computed by this apparatus, was 1 degree, and this confirmed the formation of an A-plate-type retardation film.

As computed from the retardation measured by the use of the above apparatus and from the thickness of the retardation film measured by the use of a confocal laser thickness meter (Keyence's FV-7510), Δn at a wavelength of 550 nm was 0.208, and the haze was 0.08.

Examples 31 to 43

Liquid-crystal composition coating liquids were prepared in the same manner as above except that the compounds synthesized in the above were used in place of the exemplary compound (I′-2). Using the coating liquids and in the same manner as in Example 30, retardation films of Examples 31 to 43 were produced.

These retardation films all exhibited good orientation performance and had a low haze of at most 0.1. The data of Δn of the retardation films, as determined in the same manner as in Example 30, are collectively shown in the following Table.

Comparative Example 8

A liquid-crystal composition coating liquid (2) comprising the following ingredients was prepared in the same manner as in Example 30.

Polymerizing Liquid-Crystal Compound (R-1) 100 parts by mass mentioned above Air-Interface Alignment Agent (1) 0.1 parts by mass Polymerization Initiator IRGACURE 819 (by 3 parts by mass Ciba Japan) Solvent, chloroform 800 parts by mass

A retardation film of Comparative Example 8 was produced in the same manner as in Example 30 except that the liquid-crystal composition coating liquid (2) was used in place of the liquid-crystal composition coating liquid (1). However, since the liquid crystal uppermost temperature of the polymerizable composition was lower than that of the exemplary compound (I′-2), the temperature for alignment ripening in this case was 90° C. During the period after coating and before heating, a liquid crystal partly deposited on the coating film. Accordingly, even after this was reheated and further processed for alignment ripening, some thickness unevenness still remained in the crystal-deposited part of the film.

As measured according to the same method as in Example 30, Δn at a wavelength of 550 nm of the retardation film of Comparative Example 8 was 0.256, and the haze thereof was 0.18.

Comparative Example 9

A liquid-crystal composition coating liquid (3) comprising the following ingredients was prepared in the same manner as in Example 30.

Polymerizing Liquid-Crystal Compound (R-2) 100 parts by mass mentioned above Air-Interface Alignment Agent (1) 0.1 parts by mass Polymerization Initiator IRGACURE 819 (by 3 parts by mass Ciba Japan) Solvent, chloroform 800 parts by mass

A retardation film of Comparative Example 9 was formed in the same manner as in Example 30 except that the liquid-crystal composition coating liquid (3) was used in place of the liquid-crystal composition coating liquid (1). However, since the liquid crystal uppermost temperature of the polymerizable composition was lower than that of the exemplary compound I′-2, the temperature for alignment ripening in this case was 90° C. During the period after coating and before heating, a liquid crystal partly deposited on the coating film. Accordingly, even after this was reheated and further processed for alignment ripening, some thickness unevenness still remained in the crystal-deposited part of the film.

As measured according to the same method as in Example 30, Δn at a wavelength of 550 nm of the retardation film of Comparative Example 9 was 0.360, and the haze thereof was 0.13.

The above results are shown in the following Table.

TABLE 5 Tested Compound Δn Haze Example 30 Compound (I′-2) 0.273 0.07 Example 31 Compound (I′-5) 0.275 0.08 Example 32 Compound (I′-6) 0.271 0.09 Example 33 Compound (I′-4) 0.251 0.06 Example 34 Compound (I′-3) 0.258 0.06 Example 35 Compound (I′-1) 0.276 0.07 Example 36 Compound (I′-9) 0.280 0.07 Example 37 Compound (I′-13) 0.260 0.05 Example 38 Compound (I′-15) 0.262 0.07 Example 39 Compound (II′-1) 0.260 0.09 Example 40 Compound (I′-7) 0.278 0.06 Example 41 Compound (I′-12) 0.276 0.08 Example 42 Compound (I′-10) 0.274 0.09 Example 43 Compound (I′-11) 0.260 0.06 Comparative Compound R-1 0.256 0.18 Example 8 Comparative Compound R-2 0.360 0.13 Example 9

From the results shown in the above Table, it is understood that the retardation films formed by the use of the compound of the general formula (I′) in the invention have a large Δn and a small haze as compared with the retardation film formed by the use of the conventional, monoazomethine-type polymerizing liquid-crystal compound (R-1). In addition, it is also understood that, while the film formed by the use of the conventional, bis-Schiff-type polymerizing liquid-crystal compound (R-2) is yellow, the retardation films of Examples of the invention are all white and have a small haze.

6. Production and Evaluation of Selective Reflection Films (Examples 44 to 57, Comparative Examples 10 and 11) Example 44

Using the exemplary compound (I′-2) of the formula (I′) in the invention, as synthesized in the above, a liquid-crystal composition coating liquid (11) comprising the following ingredients was prepared.

Exemplary Compound (I′-2) 33 parts by mass Polymerizing Liquid-Crystal Compound (R-3) 67 parts by mass Chiral Agent, Paliocolor LC756 (by BASF) 3 parts by mass Air-Interface Alignment Agent (1) 0.04 parts by mass Polymerization Initiator IRGACURE 819 (by 3 parts by mass Ciba Japan) Solvent, chloroform 300 parts by mass

The liquid-crystal composition coating liquid (11) was applied onto the surface of the alignment film of the alignment film-having substrate as produced in the same manner as in Example 30, according to a spin coating method at room temperature, then heated at 120° C. for 3 minutes for alignment ripening, and thereafter photoirradiated with a high-pressure mercury lamp, from which the short-wavelength UV ingredient had been removed, in a nitrogen gas atmosphere at room temperature for 10 seconds for alignment fixation to thereby produce a selective reflection film of Example 44. During the period after coating and before heating, the coating film did not crystallize.

The obtained selective reflection film was observed with a polarizing microscope, which confirmed uniform monoaxial orientation with no orientation defect in the film. Further, the transmission spectrum of the film was measured with a spectrophotometer, Shimadzu's UV-3100PC, and the spectrum had a selective reflection peak in the IR region having a center at 1000 nm, and the half-value width of the peak was 134 nm. As computed from the peak half-value width and the helical period of the polymerizable composition, Δn at a wavelength of 1000 nm was 0.211. The haze, as measured with a haze meter, Nippon Denshoku's NHD2000, was 0.07.

Examples 45 to 57

Liquid-crystal composition coating liquids were prepared in the same manner as in Example 44 except that the exemplary compounds synthesized in the above were used in place of the exemplary compound (I′-2). Using the coating liquids and in the same manner as in Example 44, selective reflection films of Examples 45 to 57 were produced. These selective reflection films all exhibited good orientation. As similarly determined, the peak half-value width of the selective reflection films and Δn thereof obtained from the former are collectively shown in the following Table.

Comparative Example 10

In the same manner as in Example 44, a liquid-crystal composition coating liquid (12) comprising the following ingredients was prepared.

Polymerizing Liquid-Crystal Compound (R-1) 33 parts by mass Polymerizing Liquid-Crystal Compound (R-3) 67 parts by mass Chiral Agent, Paliocolor LC756 (by BASF) 2.8 parts by mass Air-Interface Alignment Agent (1) 0.04 parts by mass Polymerization Initiator IRGACURE 819 (by 3 parts by mass Ciba Japan) Solvent, chloroform 300 parts by mass

A selective reflection film of Comparative Example 10 was produced in the same manner as in Example 44 except that the liquid-crystal composition coating liquid (12) was used in place of the liquid-crystal composition coating liquid (11). However, since the liquid crystal uppermost temperature of the polymerizable composition was lower than that of the composition used in Example 44, the temperature for alignment ripening in this case was 90° C. During the period after coating and before heating, a liquid crystal partly deposited on the coating film. Accordingly, even after this was reheated and further processed for alignment ripening, some thickness unevenness and orientation unevenness still remained in the crystal-deposited part of the film.

The obtained selective reflection film of Comparative Example 10 had a selective reflection peak in the IR region having a center at around 1000 nm, and the half-value width of the peak was 120 nm. As computed from the peak half-value width and the helical period of the polymerizable composition, Δn at a wavelength of 1000 nm was 0.190.

Comparative Example 11

In the same manner as in Example 29, a liquid-crystal composition coating liquid (13) comprising the following ingredients was prepared.

Polymerizing Liquid-Crystal Compound (R-2) 33 parts by mass Polymerizing Liquid-Crystal Compound (R-3) 67 parts by mass Chiral Agent, Paliocolor LC756 (by BASF) 2.8 parts by mass Air-Interface Alignment Agent (1) 0.04 parts by mass Polymerization Initiator IRGACURE 819 (by 3 parts by mass Ciba Japan) Solvent, chloroform 300 parts by mass

A selective reflection film of Comparative Example 11 was produced in the same manner as in Example 44 except that the liquid-crystal composition coating liquid (13) was used in place of the liquid-crystal composition coating liquid (11).

The selective reflection film had a selective reflection peak in the IR region having a center at around 1000 nm, and the half-value width of the peak was 154 nm. As computed from the peak half-value width and the helical period of the polymerizable composition, Δn at a wavelength of 1000 nm was 0.243. The film was yellow.

The above results are shown in the following Table.

TABLE 6 Half-Value Tested Compound Δn Haze Width Color Example 44 Compound (I′-2) 0.219 0.07 136 white Example 45 Compound (I′-5) 0.208 0.07 129 white Example 46 Compound (I′-6) 0.211 0.08 131 white Example 47 Compound (I′-4) 0.205 0.05 127 white Example 48 Compound (I′-3) 0.213 0.09 132 white Example 49 Compound (I′-1) 0.220 0.07 136 white Example 50 Compound (I′-9) 0.210 0.08 130 white Example 51 Compound (I′-13) 0.202 0.06 125 white Example 52 Compound (I′-15) 0.203 0.07 126 white Example 53 Compound (II′-1) 0.198 0.08 123 white Example 54 Compound (I′-7) 0.216 0.09 134 white Example 55 Compound (I′-12) 0.203 0.07 126 white Example 56 Compound (I′-10) 0.218 0.09 135 white Example 57 Compound (I′-11) 0.208 0.08 129 white Comparative Compound R-1 0.190 0.18 120 white Example 10 Comparative Compound R-2 0.243 0.15 154 yellow Example 11

From the results shown in the above Table, it is understood that the selective reflection films produced by the use of the compounds of the general formula (I′) in the invention have a larger Δn and have a broader selective reflection range, as compared with the selective reflection film produced by the use of the conventional, monoazomethine polymerizing liquid-crystal compound (R-1). Further, it is also understood that, while the film produced by the use of the conventional, bisazomethine polymerizing liquid crystal (R-2) is yellow, the selective reflection films of Examples of the invention are all colorless.

While the present invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

The present disclosure relates to the subject matter contained in International Application No. PCT/JP2011/064256, filed Jun. 22, 2011, Japanese Application No. 2010-141467, filed Jun. 22, 2010, and Japanese Application No. 2010-141468, filed Jun. 22, 2010, the contents of which are expressly incorporated herein by reference in their entirety. All the publications referred to in the present specification are also expressly incorporated herein by reference in their entirety.

The foregoing description of preferred embodiments of the invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or to limit the invention to the precise form disclosed. The description was selected to best explain the principles of the invention and their practical application to enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention not be limited by the specification, but be defined claims set forth below. 

What is claimed is:
 1. A polymerizable composition containing at least one compound represented by the following formula (A):

wherein P¹ and P² each represent a polymerizable group; m1 and m2 each indicate an integer of from 1 to 10, and of m1 or m2 CH₂'s, one CH₂ or two or more CH₂'s not adjacent to each other may be replaced by an oxygen atom or a sulfur atom; n1 is 0, 1 or 2; n2 is 1 or 2; A¹, A², A³ and A⁴ each represent a substituted or unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue; R represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, however, when n1 is 1 or 2, R may be an alkyl group having from 5 to 8 carbon atoms; Z¹ and Z² each represent —COO—, —OCO—, —NHCO— or —NR¹CO—, and R¹ represents an alkyl group having from 1 to 10 carbon atoms, however, when n1 is 0, Z² may be —OCO—CH═CH—; L¹ and L² each represent —O—, —S—, —COO—, —OCO—, —OCOO—, —NHCO— or —NR¹CO, and R¹ represents an alkyl group having from 1 to 10 carbon atoms, however, when n1 is 0, L¹ and L² each may be —OCO—CH═CH—.
 2. The polymerizable composition according to claim 1, which contains, as the compound represented by the formula (A), at least one compound represented by the following formula (I):

wherein P¹ and P² each represent a polymerizable group; m1 and m2 each indicate an integer of from 1 to 10, and of m1 or m2 CH₂'s, one CH₂ or two or more CH₂'s not adjacent to each other may be replaced by an oxygen atom or a sulfur atom; A¹, A² and A³ each represent a substituted or unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue; R represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; Z¹ represents —COO—, —OCO—, —OCO—CH═CH—, —NHCO— or —NR¹CO, and R¹ represents an alkyl group having from 1 to 10 carbon atoms; L¹ and L² each represent —O—, —S—, —COO—, —OCO—, —OCO—CH═CH—, —OCOO—, —NHCO— or —NR¹CO, and R¹ represents an alkyl group having from 1 to 10 carbon atoms; n1 is 1 or
 2. 3. The polymerizable composition according to claim 2, wherein A¹, A² and A³ each are an unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue, or at least one of A¹, A² and A³ is a 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue substituted with an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, an amide group having from 2 to 5 carbon atoms, an alkoxycarbonyl group having from 2 to 5 carbon atoms, an acyloxy group having from 2 to 5 carbon atoms, an acyl group having from 2 to 5 carbon atoms, a cyano group or a halogen atom.
 4. The polymerizable composition according to claim 2, wherein, in the formula (I), n1 is 1, and A¹, A² and A³ each are 1,4-phenylene optionally having a substituent.
 5. The polymerizable composition according to claim 2, wherein, in the formula (I), L¹ and L² each are —O—, and Z¹ is —OCO— or —OCO—CH═CH—.
 6. The polymerizable composition according to claim 1, which contains, as the compound represented by the formula (A), at least one compound represented by the following formula (I′):

wherein P¹ and P² each represent a polymerizable group; m1 and m2 each indicate an integer of from 1 to 10, and of m1 or m2 CH₂'s, one CH₂ or two or more CH₂'s not adjacent to each other may be replaced by an oxygen atom or a sulfur atom; A¹, A², A³ and A⁴ each represent a substituted or unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue; R represents a hydrogen atom or an alkyl group having from 1 to 8 carbon atoms; Z¹ and Z² each represent —COO—, —OCO—, —NHCO— or —NR¹CO—, and R¹ represents an alkyl group having from 1 to 10 carbon atoms; L¹ and L² each represent —O—, —S—, —COO—, —OCO—, —OCOO—, —NHCO— or —NR¹CO, and R¹ represents an alkyl group having from 1 to 10 carbon atoms; n1 and n2 each are 1 or
 2. 7. The polymerizable composition according to claim 6, wherein, in the formula (I′), A² and A³ each are 1,4-phenylene optionally having a substituent, and n1=n2=1.
 8. The polymerizable composition according to claim 7, wherein, in the formula (I′), A¹ and A⁴ each are 1,4-phenylene.
 9. The polymerizable composition according to claim 6, wherein A¹, A², A³ and A⁴ each represent an unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue, or at least one of A¹, A², A³ and A⁴ is a 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue substituted with an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, an amide group having from 2 to 5 carbon atoms, an alkoxycarbonyl group having from 2 to 5 carbon atoms, an acyloxy group having from 2 to 5 carbon atoms, an acyl group having from 2 to 5 carbon atoms, a cyano group or a halogen atom.
 10. The polymerizable composition according to claim 1, wherein, in the formula (A), P¹ and P² each are a polymerizable group selected from the groups represented by the following formulae (P-1) to (P-5):

wherein R¹¹ to R¹³ each represent a hydrogen atom or a methyl group.
 11. The polymerizable composition according to claim 1, wherein, in the formula (A), P¹ and P² each are a methacrylate group or an acrylate group.
 12. The polymerizable composition according to claim 1, wherein, in the formula (A), m1 and m2 each are an integer of from 2 to
 8. 13. The polymerizable composition according to claim 1, which contains at least one chiral compound.
 14. A polymer produced by polymerizing a polymerizable composition containing at least one compound represented by the following formula (A):

wherein P¹ and P² each represent a polymerizable group; m1 and m2 each indicate an integer of from 1 to 10, and of m1 or m2 CH₂'s, one CH₂ or two or more CH₂'s not adjacent to each other may be replaced by an oxygen atom or a sulfur atom; n1 is 0, 1 or 2; n2 is 1 or 2; A¹, A², A³ and A⁴ each represent a substituted or unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue; R represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, however, when n1 is 1 or 2, R may be an alkyl group having from 5 to 8 carbon atoms; Z¹ and Z² each represent —COO—, —OCO—, —NHCO— or —NR¹CO—, and R¹ represents an alkyl group having from 1 to 10 carbon atoms, however, when n1 is 0, Z² may be —OCO—CH═CH—; L¹ and L² each represent —O—, —S—, —COO—, —OCO—, —OCOO—, —NHCO— or —NR¹CO, and R¹ represents an alkyl group having from 1 to 10 carbon atoms, however, when n1 is 0, L¹ and L² each may be —OCO—CH═CH—. a substituted or unsubstituted
 15. A film containing at least one polymer produced by polymerizing a polymerizable composition containing at least one compound represented by the following formula (A):

wherein P¹ and P² each represent a polymerizable group; m1 and m2 each indicate an integer of from 1 to 10, and of m1 or m2 CH₂'s, one CH₂ or two or more CH₂'s not adjacent to each other may be replaced by an oxygen atom or a sulfur atom; n1 is 0, 1 or 2; n2 is 1 or 2; A¹, A², A³ and A⁴ each represent a substituted or unsubstituted, 5- to 18-membered aromatic hydrocarbon ring or 5- to 18-membered aromatic hetero ring residue; R represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, however, when n1 is 1 or 2, R may be an alkyl group having from 5 to 8 carbon atoms; Z¹ and Z² each represent —COO—, —OCO—, —NHCO— or —NR¹CO—, and R¹ represents an alkyl group having from 1 to 10 carbon atoms, however, when n1 is 0, Z² may be —OCO—CH═CH—; L¹ and L² each represent —O—, —S—, —COO—, —OCO—, —OCOO—, —NHCO— or —NR¹CO, and R¹ represents an alkyl group having from 1 to 10 carbon atoms, however, when n1 is 0, L¹ and L² each may be —OCO—CH═CH—. a substituted or unsubstituted
 16. The film according to claim 15, produced by fixing the cholesteric liquid-crystal phase of the polymerizable composition.
 17. The film according to claim 15, which shows optical anisotropy.
 18. The film according to claim 15, which shows selective reflection characteristics.
 19. The film according to claim 18, which shows selective reflection characteristics in the IR wavelength range.
 20. The film according to claim 15, which is colorless. 